Automatic cut-off



March 27, 1934. G ND 1,952,265

AUTOMATIC GUT-OFF Filed Dec. 31, 1929 2 Sheets-Sheet 1 //\/\/'NTOR.GEORGE H. LELAND.

ATTORNEY March 27, 1934. G, H ND 1,952,265

AUTOMATIC CUT-OFF Filed Dec. 51, 1929 2 Shee'is-Sheet 2 Z4 //\/VENTOR.25 GEORGE H. LELAND.

4 TTORNEY Patented Mar. 27, 1934 PATENT OFFICE AUTOMATIC CUT-OFF GeorgeH. Leland, Dayton, Ohio, assignor of onehalf to The Leland ElectricCompany, a corporation of Ohio Application December 31, 1929, Serial No.417,683

2 illaims.

This invention relates to an automatic cut-off and is designed primarilyfor controlling the operation of an apparatus for supplying fluid fuelto burners. In certain apparatus of this kind the fluid fuel, or one ofthe constituent elements thereof, is delivered to a container, underpressure, by a motor operated pump, the container being connected withthe burners. Such an ap paratus is usually supplied with a pressurecontrolled device for so operating a switch in the motor circuit as tomaintain the pressure within the container between certain predeterminedlimits. It is desirable, however, that means should also be provided foropening the motor switch when the pressure within the container falls toan abnormally low level. For example, should the supply of current tothe motor circuit be interrupted and the motor switch closed by the fallof pressure to the normal low limit the motor would, of course, fail tooperate and ii a burner was lighted the pressure in the container wouldcontinue to fall until it was no longer sufiicient to supply fuel to theburner and the flame of the burner would then be extinguished. Ifsubsequently the supply of current to the motor circuit was restored themotor would immediately begin to operate and to build up pressure in thecontainer, thus causing fuel to be delivered to the burner where itwould escape into the atmosphere. Not only would this result in a wasteof fuel but it would be liable to cause an accumulation of gas in theroom in which the burner was located, which might result in anexplosion. In cut-offs of this type as heretofore manufactured it hasbeen customary to provide a separate pressure controlled device foropening the switch when the pressure falls to a predetermined abnormallylow level. Such a second controlling device not only increases the costof 40 the mechanism but it complicates the mechanism and the operationthereof and renders the same more difiicult of maintenance.

One object of the present invention is to provide such a mechanism inwhich a single controlling deyice, which may be controlled by fluidpressure or otherwise, will operate the cut-off both under normalconditions and under abnormal conditions.

A further object of the invention is to provide such a; mechanism inwhich a single pressure' controlled device will open the cut-oii at apredetermined high pressure, will close the cutofi at a normally lowpressure and will again open the cut-off at an abnormally low pressure.

A further object of the invention is to provide such a mechanism havinga single operating member which will actuate the cut-off both underpredetermined normal conditions and under predetermined abnormalconditions.

A further object of the invention is to provide such a mechanism havingan operating member, the movement of which in one direction will openthe cut-oil and the continued movement of which in the other directionwill first close the cutoff and then open the same.

A further object of the invention is to provide such a mechanism inwhich the cut-off will be moved quickly from one position to the other.

Other objects of-the invention will appear as the mechanism is describedin detail.

In the accompanying drawings Fig. 1 is a horizontal section takenthrough the casing ofa mechanism embodying my invention and showing themechanism in plan; Fig. 2 is a front elevation of such an apparatus withthe closure removed and showing the operating mechanism in elevation andpartly broken away; Fig. 3 is a sectional detail view showing theoperating parts in a position to maintain the cut-off closed; Fig. 4- isa similar view showing the operating parts in the position to which theyare moved when the pressure reaches its normal high limit; Fig. 5 is asimilar view showing the parts in positions to which they are moved whenthe pressure reaches an abnormal low limit; Fig. 6 is a detail view ofthe actuating plate for the cut-off; Fig. '7 is a detail view of thesupporting bracket for the actuating plate; Fig. 8 is a circuit diagram;and Fig. 9 is a detail view of the resetting device.

In these drawings I have illustrated one embodiment of my invention andhave shown the same in the form of a pressure controlled electricalcut-oiT or switch, but it will be understood that this particularembodiment has been chosen for the purpose of illustration only and thatthe mechanism may take various forms and may be used in connection withcut-offs of various kinds.

In that embodiment here illustrated the mechanism comprises a supportingstructure 10 which is preferably in the form of a casing having a 100removable front wall or closure 11. The cut-oft is preferably mountedupon the supporting structure and, in the present instance, it is shownin the form of an electrical switch mounted within the casing. Anysuitable type of switch may be 105 employed but the one here shown is inthe form of a mercury tube 12 mounted for pivotal movement and havingwithin the same two contact members 13 and 14 which are connected byflexible conductors 15 and 16 with terminals 17 and 110 18 which in turnare connected with the circuit 19 of a motor. The motor is not hereshown but in a gas apparatus of the type above mentioned it wouldoperate a pump to deliver fluid to the container. The mercury tube issupported by clips 20 secured to and depending from a supporting plate21 which is pivotally mounted for movement about an axis transverse tothe length of the tube and constitutes an actuating device for thecut-off or switch. The tube contains mercury in such quantity that whenthe tube is in a substantially horizontal position the mercury willengage both the contacts 13 and 14 and close the circuit through themotor. When the actuating plate 21 is moved about its axis to tiltthetube the mercury will move to one end of the tube and out ofengagement with one or both of the contacts, thereby interrupting thecircuit through the motor. The supporting plate may be pivotally mountedin any suitable manner but in order to reduce the friction as far aspossible I have provided the same with knife edged bearings. In thepresent construction the actuating plate has on the respective sidesthereof oppositely facing knife edges, 22 and 23, arranged in axialalinement and seated in V-bearings in the depending arms 24 and 25 of asupporting bracket 26 which, in the present instance, is secured-to thetop wall of the casing. The knife edges are held in contact with theirbearings by means of a spring which will be hereinafter described.

The actuating plate 21 is moved about its axis to tilt the switch bymeans of an operating member 27 which, in the present instance, is inthe form of an elongated plate or lever pivotally mounted at one end onthe end wall of the casing, as shown at 28, and is provided with anopening 29 through which the arms of the bracket 26 extend so that theoperating member is arranged directly above the actuating plate. Thisoperating member is of such a character and is so arranged that when itis in an intermediate position, which may be characterized as its normalposition, the actuating plate 21 will be in a substantially horizontalposition and the switch will be closed. If the operating member is movedupwardly from its normal intermediate position the actuating plate willbe moved about its axis and the switch tilted to an open position. Ifthe operating member moves downwardly from its normal intermediateposition the actuating memher will be moved about its axis in the samedirection to again tilt the switch to its open position. In the presentconstruction the operating member has at one edge thereof a dependingflange 30, the outer end portion of which is so shaped as to provide afinger 31 which extends inwardly beneath a lug 32 extending laterallyfrom the actuating plate 21 on the outer side of its axis. Anintermediate portion of the flange 30 extends above and is adapted toengage a second lug 33 extending laterally from the actuating plate onthe inner side of its axis. The arrangement is such that either theupward or downward movement of the operating member from its normalintermediate position will cause the actuating plate to be tilted toopen the switch.

The movement of the operating member is controlled by a controllingdevice and, in the present instance, this controlling device iscontrolled by the fluid pressure in the container. As here shown, a stud34 is secured to and depends from the operating lever 27 at a pointspaced a short distance from its axis and this stud has in its lower enda recess 35 to receive the pointed upper end of a plunger 36 which isslidably mounted in a bearing or boss 37 on the bottom wall of thecasing. The lower end of the plunger extends through the bottom wall ofthe casing and into a housing 38 carried by the casing and within whichthe plunger is connected with a pressure operated member, such as asylphon 39. The housing 38 is fluid tight and is connected by a pipe 40with the container so that the fluid pressure within the housing will bethe same as that within the container. The pressure within the housingacts on the sylphon in a direction to impart upward movement to theplunger and this movement is resisted by a spring 41 connected with thelever. In the present instance, the spring 41 is coiled about theplunger and has its ends mounted in screw threads carried by the stud 34and the boss 3'7, the threads on the stud being left hand threads andthe threads on the boss being right hand threads, whereby the rotationof the spring will cause the end portions thereof to be moved toward orfrom each other and the tension of the spring varied.

Interposed between the actuating plate 21 and the operating lever 27 isa spring 42 which has several functions. In the present arrangement, theactuating plate has a finger 43 extending outwardly from the inner endthereof and spaced some distance from the body of the plate. This fingerhas a bearing point 44 arranged substantially in the vertical plane ofthe axis of the plate but spaced a short distance below that axis. Theoperating lever has at its outer end a depending lug 45 in which ismounted an inwardly extending finger 46 having a bearing point and hereshown as a screw adjustably mounted in the lug. The spring 42 is acompression spring and is provided at each end with conical seats 4'? toreceive the respective bearing points 44 and 46. The spring 42 isnormally under pressure and because of the offset position of the arm 43with relation to the body of the plate 21 the spring tends normally tomove the actuating plate about a vertical axis in a direction to causethe knife edges 22 and 23 to be held firmly in contact with theirbearings. The bearing point 44 of the arm 43 being slightly below theaxis of the actuating plate this spring also tends to move the plateabout its transverse axis in a direction to hold the lugs 32 and 33 inengagement with the finger 31 and flange 30 of the operating member,thereby stabilizing the actuating plate and firmly retaining the switchin its closed position so long as the operating member is in itsintermediate position. The bearing points 46 of the operating member and44 of the actuating plate are approximately in a line extending throughthe axis 28 of the operating member. The point 44 is slightly below thisline when the parts are in the intermediate positions shown in Figs. 2and 3 but it is so nearly in line with the point 46 and the axis 28 thatthe spring will tend to hold the operating member against movement aboutsaid axis.

With the parts in the positions shown in Figs. 2 and 3, the switch isclosed and the motor operating and the pressure in the container and inthe housing 38 will gradually rise. The resistance of the spring 42 tothe movement of the operating member 27 is such that the plunger 36 ofthe controlling device will be held against movement until the pressurein the housing 38 has reached a predetermined high point, say sevenpounds. This high pressure will be sufiicient to overcome 'sure withinthe container.

the action of the spring 42 and the operating lever will be moved aboutits axis. As soon as the bearing point 46 of the operatinglever is movedsubstantially out of line with the point 44 of the actuating plate andthe axis 28 of the operating lever the spring 42 will expand to move thelever quickly to the limit of its movement thereby causing the mercurytube to be quickly tilted and the circuit broken, as shown in Fig. 4. Ashere shown, a lug or pad 48 depending from the top wall of the casingforms a stop to limit the upward movement of the operating lever. As thepressure in the housing 38 falls the spring 41 of the controlling devicewill exert a downward pull upon the operating lever and this pull isresisted by the spring 42 until the pressure has fallen to apredetermined point, say four pounds, at which time the spring 41 willovercome the spring 42 and the lever will be moved to its intermediateposition. The spring 42 acting upon the finger 43 of the actuating platewill cause that plate to move with the operating lever and thus restorethe cut-off to its closed position, as shown in Fig. 3. Should the motorfail to operate when the circuit is thus again closed the pressure inthe housing 38 will continue to fall until its reaches a predeterminedabnormally low point, say two pounds, when the tension of the spring 41of the controlling device is sufficient to overcome the spring 42 andmove the operating lever downwardly, thus carrying the bearing point 46out of line with the bearing point 44 and the axis 28 and causing theoperating lever to be moved quickly to the lower limit of its movement.During this movement the flange 30 will act on the lug 33 of theactuating plate to tilt the. same to the position shown in Fig. 5, thusagain opening the circuit. The motor circuit being opened there-establishing of the current supply to the motor circuit will notcause the operation of the motor and it is necessary that the motor orpump should be operated in some manner to restore the pres- This may bedone in various Ways. In the present instance, the operating lever isprovided with a finger 49 which ex tends laterally to a point near thefront wall 11 of the casing. Pivotally mounted on the inner side of thefront wall is a resetting member 51 which has a finger piece 52extending through a slot 53 in the wall. The resetting member is'somounted that it will normally move to its lowermost position, as shownin dotted lines in Fig. 9. When the operating lever has moved downwardlyfrom its intermediate position the finger 49 will lie just above theresetting member and when that member is moved about its axis by thefinger piece 52 it will engage the finger 49 and lift the operatingmember to its normal or intermediate position, thus closing the circuitand starting the motor. The upper edge of the resetting member has flatcontact with the finger 49 and the thrust of the operating lever willhold the resetting member in its operative position, thus retaining theswitchin its closed position and permitting the pressure to build up inthe container. When the pressure becomes sufficient to lift theoperating lever above its normal position the resetting member will bereleased and drop to its lowermost position. If desired, the motor maybe provided with an auxiliary circuit having a manually operatedswitchby means of which the circuit can be closed through the motorindependently of the circuit 19 and the motor thus caused to operate tobuild up the pressure in the container,

which would automatically restore the operating member 27 and the otherparts to their normal positions. The switch for such an auxiliarycircuit should be of such a type that it will automatically open whenthe pressure thereon is relieved, such as a push button, so as to avoidthe possibility of this auxiliary circuit being permitted to remainclosed; Such an auxiliary circuit is shown at 50 in the circuit diagramof Fig. 8.

The operation of the device will be readily understood from theforegoing description and it will be apparent that the mechanism thereshown may be used, either with or without modification, to operatecut-offs of various kinds and that the movement of the operating membermay be controlled in any suitable manner, as by means of a thermostat orvoltage controlled solenoid. Thermostats and solenoids of this type arewell known and it will be obvious that they could be substituted for thepressure operated device of the application and would constitute thefull equivalent thereof.

While I have shown and described one embodiment of my invention I wishit to be understood that I do not desire to be limited to the detailsthereof as various modifications may occur to a person skilled in theart.

Having now fully described my invention, what I claim as new and desireto secure by Letters Patent, is:

1. In a mechanism for operating a cut-off, an actuating plate connectedwith said cut-off and having on the respective sides thereof oppositelyfacing knife edges, open bearings to receive said knife edges, saidactuating plate having a finger extending transversely to its axis andhaving one end arranged substantially in line with but slightly belowsaid axis, a pivoted operating member having a part arranged to engagethe upper surface of said actuating plate on one side of its axis and apart to engage the lower surface of said actuating plate on the otherside of its axis, said operating member having a depending portionarranged on.that side of said actuating plate remote from the axis ofsaid operating member,

said depending portion having a finger arranged side thereof a fingerspaced from the adjacent knife edge and depressed below the axis of saidplate, a lever pivotally mounted at one end on said supportingstructure, arranged above said plate and having a part to engage theupper surface of said plate on one side of the axis thereof,

and having another part to engage the lower surface of said plate on theother side of the axis thereof, said operating member also having afinger'secured thereto but spaced below the same and arrangedsubstantially in line with the finger of said plate and the axis of saidlever, a spring confined between said fingers, and means for impartingmovement to said lever.

GEORGE H. LELAND.

